Apparatus and method for forming an antipollution device housing

ABSTRACT

A tool assembly for forming a workpiece into a housing with a non-round design outer profile at least partially defined by an outer surface at a design position reduced from the initial position thereof. The tool assembly includes a ring portion having a bore therein at least partially defined by an inner surface, and an insert portion with a back plate and a number of elongate jaw segments, each jaw segment having between a back end thereof engaged with the back plate. When the insert portion is moved from an open condition to a closed condition, the inner surface of the ring portion urges the jaw segments inwardly, causing the jaw segments to engage substantially the entire outer surface and to move the outer surface from an initial position to the design position, reducing an initial outer profile to the design outer profile and forming the workpiece into the housing.

This application is a continuation of International patent applicationno. PCT/CA2010/001194, filed on Jul. 30, 2010, which claims the benefitof U.S. Provisional Application No. 61/229,920, filed on Jul. 30, 2009,each of which is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention is an apparatus and a method for forming anantipollution device housing.

BACKGROUND OF THE INVENTION

Various antipollution devices for use in automotive exhaust systems areknown. Two common examples are the catalytic converter and the dieselparticulate filter (“DPF”). Such known antipollution devices typicallyinclude housings in which certain components are positioned.

Within the main portion of the housing of a typical antipollution deviceis assembled a honeycomb-like structure (i.e., a “brick”) most commonlymade of a suitable ceramic substrate or similar material. (Othermaterials, e.g., stainless steel honeycombs, are also sometimes used asthe substrate.) The brick provides a structure to which is appliedvarious precious metals which act as the catalyst. The brick is a veryfragile structure and is easily damaged, and because of this it isusually wrapped in a supportive, intumescent, mat inside the mainportion of the housing. As is well known in the art, the main portion ofthe housing typically is sized to accommodate the brick and the mattherein, and the sizing of the housing is very important.

In general, the mat is critical to the overall performance of theantipollution device. The mat is required to seal the surfaces betweenthe outer perimeter of the brick and the inner perimeter of the housing(i.e., in the main portion) to ensure that substantially all exhaustpasses through the brick and is exposed to the catalyst, so that theundesired emissions are processed. In addition, the mat also imparts theproper forces within the housing to ensure the brick is not fractureddue to excessive force, but is subjected to sufficient force to properlymaintain and hold the brick in the correct position within the housingwithout slippage. As is well known in the art, according to design, themat is to be compressed to a predetermined extent (e.g., so as to have apredetermined gap bulk density (“GBD”)).

As is well known in the art, housings for antipollution devices areprovided in a variety of shapes in cross-section. For example, incross-section, the housings may have the following shapes: round, ovals,rectangles, squares, trapezoids, and many variations of such shapes,including irregular shapes. It is also known that antipollution devicehousings are often designed to receive a single brick, but alternativelyare also often made with several bricks because of the performancerequirements in a particular application.

A number of problems have arisen in connection with the known methods ofmanufacturing antipollution devices. The methods of the prior art haveresulted in many failures due to inaccurate forming of the main portionand the transition portions in relation to the dimensions of the mat andthe brick(s) which are assembled within the particular housing. Forinstance, if the housing is incorrectly formed too large, then themat/brick subassembly slides in relation to the housing, resulting indamage to the brick and/or mat and, as a direct consequence, theimmediate failure of the antipollution device when it is used. On theother hand, if the housing is sized too small or too tight, theantipollution device either cannot be assembled or the mat/bricksubassembly is damaged during the assembly process, which typicallyresults in impaired performance or failure of the antipollution device.

Various methods of assembling the brick and the mat in the housing areknown in the art. For instance, it is known to provide a housing whichis somewhat larger than required for a particular brick/mat subassembly.In this situation, the housing is formed from a workpiece which isreduced in size after the brick/mat assembly is positioned in theworkpiece, to the required size and shape for the brick/mat subassembly.It is also known in the prior art to provide a housing which is requiredto be expanded in order to accommodate the brick/mat subassembly.

If the housing is properly formed to the correct dimensions of theindividual brick/mat assembly, then the assembled antipollution devicewill satisfy the necessary GBD and/or other required inspectioncriteria. However, because the tolerance is relatively fine, even asmall deviation from the required dimensions of the housing can resultin an unacceptable assembly.

Depending on the variability of the brick and the mat, each housing maybe required to be sized to unique and variable sizes based on thecomponents that will be assembled within the housing. However, it isalso known that, for a particular design, each shell may be reduced tosubstantially the same inner design dimensions, if the brick and the matare manufactured to suitable tolerances.

In the prior art, where a shell has a non-round profile (e.g., oval) andthe workpiece is required to be reduced by more than approximately 2millimeters, the shell is not satisfactorily formed. This is because, inthe prior art, the tool segments are moved toward a common center as theworkpiece is formed into the shell (FIG. 1A). However, in the prior art,the tool segments (or jaw segments) are not movable at a uniform rate(i.e., the prior art jaw segments do not engage the workpiecesubstantially simultaneously), resulting in ridges (not shown) in theshell when the size reduction is greater than about 2 millimeters.Because many designs now require far more than a 2 millimeter reduction,this means that the shell or housing is often not satisfactorily formed.

In the prior art, the housing is often formed in a process in which atleast two, and sometimes three or more different machine heads are usedin an attempt to address this problem, i.e., in an attempt to ensurethat each housing is appropriately formed. Using this many machinesinvolves a relatively high unit expense and also requires time to bespent in the manufacturing process moving the workpiece betweenmachines. Also, the use of multiple machines has not necessarilyresulted in satisfactory reduction of the non-round profile by 2millimeters or more.

A typical prior art tool assembly 20 to be used for reduction of anon-round profile by 2 millimeters or more is shown in FIGS. 1A-1D. (Aswill be described, the remainder of the drawings illustrate the presentinvention.) As is well known in the art, the tool assembly 20 typicallyincludes a ring portion 17 with a round tapered inner bore thereindefined by an inner surface 19 and an inner segmented subassembly 21including a number of jaw segments 22. However, where the workpiece isreduced by 2 millimeters or more to form the non-round housing, theprior art tool assembly 20 has often provided unsatisfactory results, asdescribed above.

As can be seen in FIGS. 1C and 1D, the jaw segments 22, when in anengaged condition (as shown in FIGS. 1A-1D), define a substantially ovaldesign profile 24. As is well known in the art, internal surfaces 26 ofthe jaw segments 22 engage an outer surface of a workpiece (not shown inFIGS. 1A-1D) as the jaw segments move inwardly, each jaw segment 22moving as indicated by the arrows “A” toward a common center “X” (FIG.1C). The converging and forward movement of the jaw segments resultsfrom movement of a back plate (not shown) on which the jaw segments 22are mounted toward the ring portion (FIGS. 1A, 1B) with thesubstantially round tapered bore therein. Also, the convergence duringthe forward movement of the jaw segments results from engagement oftapering side surfaces 28 (FIG. 1D) with the inner surface (not shown)defining the round hole in the ring portion, as the back plate is movedtoward the ring portion.

As noted above, in practice, the prior art tool assembly generally doesnot provide a satisfactory housing with a non-round profile. The housingresulting from this processing typically has small ridges thereon. Thisdefect appears to be due to each of the jaws having a slightly differentgeometry, but each also being urged inwardly by an inner surface of thering portion which is round in cross-section, toward a common center.

SUMMARY OF THE INVENTION

For the foregoing reasons, there is a need for an improved method andapparatus for making housings for antipollution devices which address ormitigate one or more of the defects of the prior art. In particular, theapparatus of the invention provides for substantially simultaneousengagement by jaw segments of substantially the entire outer surface ofthe workpiece.

In its broad aspect, the invention provides a tool assembly for forminga workpiece with an initial outer profile at least partially defined byan outer surface thereof at an initial position into a housing with anon-round design outer profile at least partially defined by the outersurface at a design position reduced from the initial position thereof.The tool assembly includes a ring portion having a bore therein at leastpartially defined by an inner surface, and an insert portion. The insertportion includes a back plate and a number of elongate jaw segments.Each jaw segment extends between a back end thereof engaged with theback plate and a front end thereof distal to the back plate. Inaddition, each said jaw segment has an internal surface for engaging theouter surface and an at least partially tapered external surface forsliding engagement with the inner surface of the ring portion. The jawsegments are movable between a first condition, in which the internalsurfaces of the jaw segments at least partially define an opening inwhich the workpiece is receivable, and a second condition, in which theinternal surfaces of the jaw segments substantially define the designposition of the outer surface. The jaw segments being at least partiallyreceivable in the bore of the ring portion. The insert portion ismovable relative to the ring portion between an open condition of thetool assembly, in which the back plate is positioned distal to the ringportion, and a closed condition of the tool assembly, in which the backplate is positioned proximal to the ring portion. When the insertportion moves from the open condition to the closed condition, the innersurface of the ring portion urges the jaw segments inwardly from thefirst condition to the second condition, causing the jaw segments toengage substantially the entire outer surface and to move the outersurface from the initial position to the design position, reducing theinitial outer profile to the design outer profile and forming theworkpiece into the housing.

In another aspect, the jaw segments are moved along respectivesubstantially straight predetermined paths as the jaw segments are movedfrom the first condition to the second condition, the predeterminedpaths being aligned with preselected end points.

In another aspect of the invention, the jaw segments are divided into aplurality of groups. Each group has a selected one of the preselectedend points associated therewith. Each jaw segment in each group ismovable along the predetermined path therefor toward the selected one ofthe preselected end points for the group thereof as the jaw segments aremoved from the first condition to the second condition.

In another aspect, a radius centered on the preselected end point of aselected one of the groups is substantially coincident with a portion ofthe design outer profile that is substantially defined by the internalsurfaces of the jaw segments in the selected one of the groups, when thejaw segments are in the second condition.

In yet another aspect, each said jaw segment comprises a key portion,each key portion being receivable in a keyway in the back plate forguiding each said jaw segment along the predetermined path thereforrespectively.

In another aspect, each jaw segment is at least partially movable alongthe predetermined path by one or more motive means.

The invention also provides, in another of its aspects, a method forforming a workpiece with an initial outer profile at least partiallydefined by an outer surface thereof at an initial position into ahousing with a non-round design outer profile at least partially definedby the outer surface at a design position reduced from the initialposition thereof. The method includes providing a ring portion having abore therein defined by an inner surface, and providing an insertportion with a back plate, and a number of jaw segments. The jawsegments are movable between a first condition, in which the internalsurfaces of the jaw segments at least partially define an opening inwhich the workpiece is at least partially positionable, and a secondcondition, in which the internal surfaces of the jaw segmentssubstantially define the design position of the outer surface. At leastparts of the jaw segments are positioned in the bore of the ringportion. The jaw segments are moved to the first condition, and theworkpiece is inserted in the opening. Finally, the back plate is movedtoward the ring portion to engage the inner surface of the ring portionwith external surfaces of the jaw segments, to urge the jaw segmentsinwardly to the second condition so that the internal surfaces of thejaw segments engage substantially the entire outer surface and move theouter surface from the initial position to the design position, reducingthe initial outer profile to the design outer profile and forming theworkpiece into the housing.

In another of its aspects, the invention provides a tool assembly inwhich the ring portion is movable relative to the insert portion betweenan open condition of the tool assembly, in which the ring portion ispositioned distal to the back plate, and a closed condition of the toolassembly, in which the ring portion is positioned proximal to the backplate. When the ring portion moves from the open condition to the closedcondition, the inner surface of the ring portion urges the jaw segmentsinwardly from the first condition to the second condition, causing thejaw segments to engage substantially the entire outer surface and tomove the outer surface from the initial position to the design position,reducing the initial outer profile to the design outer profile andforming the workpiece into the housing.

In yet another aspect, the invention provides a method in which the ringportion is moved toward the back plate to engage the inner surface ofthe ring portion with the external surfaces of the jaw segments, to urgethe jaw segments inwardly to the second condition such that the internalsurfaces of the jaw segments engage substantially the entire outersurface and move the outer surface from the initial position to thedesign position, reducing the initial outer profile to the design outerprofile and forming the workpiece into the housing.

In another aspect, the invention provides a tool assembly in which theinsert portion and the ring portion are movable relative to each otherbetween an open condition of the tool assembly, in which the back plateis positioned distal to the ring portion, and a closed condition of thetool assembly, in which the back plate is positioned proximal to thering portion. When the ring portion and the insert portion move from theopen condition to the closed condition, the inner surface of the ringportion urges the jaw segments inwardly from the first condition to thesecond condition, causing the jaw segments to engage substantially theentire outer surface and to move the outer surface from the initialposition to the design position, reducing the initial outer profile tothe design outer profile and forming the workpiece into the housing.

In yet another aspect, the invention provides a method in which the backplate and ring portion are moved toward each other to engage the innersurface of the ring portion with the external surfaces of the jawsegments, to urge the jaw segments inwardly to the second condition suchthat the internal surfaces of the jaw segments engage substantially theentire outer surface and move the outer surface from the initialposition to the design position, reducing the initial outer profile tothe design outer profile and forming the workpiece into the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the attacheddrawings, in which:

FIG. 1A (also described previously) is a front view of a tool assemblyof the prior art;

FIG. 1B (also described previously) is a side view of the tool assemblyof FIG. 1A;

FIG. 1C (also described previously) is a front view of the jaw segmentsof FIG. 1A, drawn at a larger scale;

FIG. 1D (also described previously) is an isometric view of the jawsegments of FIGS. 1A-1C;

FIG. 2A is a front view of an embodiment of a jaw segment subassembly ofthe invention;

FIG. 2B is a an isometric view of the jaw segment subassembly of FIG.2A;

FIG. 3 is a front view of a housing with a brick and a mat positionedtherein, drawn at a larger scale;

FIG. 4 is an isometric view of an embodiment of the tool assembly of theinvention in which the jaw segments are shown in an engaged conditionengaging an outer surface, drawn at a smaller scale;

FIG. 5 is an isometric view of the tool assembly of FIG. 4 showing abrick and a mat positioned in the housing;

FIG. 6A is an isometric view of an embodiment of an insert portion ofthe invention with the jaw segments therein in a first condition, drawnat a larger scale;

FIG. 6B is an isometric view of an embodiment of a ring portion of theinvention;

FIG. 6C is an isometric view of an embodiment of the tool assembly ofthe invention;

FIG. 6D is another isometric view of the tool assembly of FIG. 6C;

FIG. 6E is another isometric view of the tool assembly of FIG. 6C, inwhich the jaw segments are in a second condition;

FIG. 6F is an isometric view of an alternative embodiment of a backplate of the invention, drawn at a larger scale;

FIG. 6G is an isometric view of the back plate of FIG. 6F with directionof movement of the ring portion and/or the insert portion schematicallyrepresented therein;

FIG. 7A is a front view of the insert portion of FIG. 6A, drawn at asmaller scale;

FIG. 7B is a side view of the insert portion of FIG. 7A;

FIG. 8A is a front view of the insert portion of FIG. 7A, in which thejaw segments are in the second condition;

FIG. 8B is a side view of the insert portion of FIG. 8A;

FIG. 9A is a top view of an embodiment of a jaw segment of theinvention, drawn at a larger scale;

FIG. 9B is a side view of the jaw segment of FIG. 9A;

FIG. 9C is a cross-section showing the jaw segment of FIG. 9A engagingthe inner surface of the ring portion, drawn at a larger scale;

FIG. 10A is a front view of the back plate of FIG. 6F, drawn at asmaller scale;

FIG. 10B is a side view of the back plate of FIG. 10A;

FIG. 11 is a front view of an embodiment of an alternative embodiment ofthe insert portion of the invention;

FIG. 12A is a front view of the back plate of FIG. 6F with a jaw segmentpositioned thereon, drawn at a smaller scale;

FIG. 12B is a side view of the back plate and jaw segment of FIG. 12A;

FIG. 13A is a front view of an alternative embodiment of the toolassembly of the invention in which the jaw segments are in the firstcondition;

FIG. 13B is a front view of a portion of the tool assembly of FIG. 13A,drawn at a larger scale;

FIG. 14 is a front view of the tool assembly of FIG. 13A in which thejaw segments are in the second condition, drawn at a smaller scale;

FIG. 15A is a schematic illustration of an embodiment of a method of theinvention;

FIG. 15B is a schematic illustration of another embodiment of the methodof the invention; and

FIG. 15C is a schematic illustration of another alternative embodimentof the method of the invention.

DETAILED DESCRIPTION

In the attached drawings, like reference numerals designatecorresponding elements throughout. Reference is first made to FIGS.2A-6E and 7A-9C to describe an embodiment of a tool assembly inaccordance with the invention indicated generally by the numeral 130.The tool assembly 130 (FIG. 4) is for forming a workpiece 132 with aninitial outer profile 134 (FIGS. 3, 7A, 7B) at least partially definedby an outer surface 135 thereof at an initial position (FIGS. 3, 7A)into a housing 136 having a non-round design outer profile 138 (FIGS. 3,8A, 8B) at least partially defined by the outer surface 135 at a designposition (FIGS. 3, 8A) reduced from the initial position thereof. Thetool assembly 130 preferably includes a ring portion 140 having a bore142 therein at least partially defined by an inner surface 144 (FIG.6B). It is also preferred that the tool assembly 130 includes an insertportion 146 having a back plate 148 and a number of elongate jawsegments 150. Each jaw segment 150 extends between a back end 152thereof engaged with the back plate 148 and a front end 154 thereofdistal to the back plate 148 (FIGS. 9A, 9B). As can be seen in FIGS. 9Aand 9B, each jaw segment 150 includes an internal surface 156 forengaging the outer surface 135 and an at least partially taperedexternal surface 158 for sliding engagement with the inner surface 144of the ring portion 140, as will be described. The jaw segments 150preferably are movable between a first condition (FIGS. 7A, 7B), inwhich the internal surfaces 156 of the jaw segments 150 at leastpartially define an opening 160 in which the workpiece 132 isreceivable, and a second condition (FIGS. 6E, 8A, 8B), in which theinternal surfaces 156 of the jaw segments 150 substantially define thedesign position of the outer surface 135 (FIGS. 8A, 8B). Preferably, thejaw segments 150 are at least partially receivable in the bore 142 ofthe ring portion 140, as will also be described. In one embodiment, theinsert portion 146 preferably is movable relative to the ring portion140 between an open condition of the tool assembly (FIG. 6D), in whichthe back plate 148 is positioned distal to the ring portion 140, and aclosed condition of the tool assembly (FIGS. 4, 5), in which the backplate 148 is positioned proximal to the ring portion 140. When theinsert portion 146 moves from the open condition to the closedcondition, the inner surface 144 of the ring portion 140 urges the jawsegments 150 inwardly (i.e., in the direction indicated by arrows “K” inFIG. 9C) from the first condition to the second condition, causing thejaw segments 150 to engage substantially the entire outer surface 135and to move the outer surface 135 from the initial position to thedesign position, reducing the initial outer profile 134 to the designouter profile 138, and forming the workpiece 132 into the housing 136.

Those skilled in the art would appreciate that, after the housing 136 isformed (i.e., usually with the brick and mat therein, as describedbelow), the insert portion 146 preferably moves from the closedcondition to the open condition. It is also preferred that, as theinsert portion 146 moves to the open condition, the jaw segments 150move outwardly from the second condition to the first condition. As thejaw segments 150 move to the first condition, the internal surfaces 156of the jaw segments 150 are released from engagement with the outersurface 135. The housing 136 is then removable from the opening 160.After the just-formed housing 136 is removed, a new workpiece 132 isthen positioned in the opening 160, and the process is repeated.

As will also be described, in one embodiment, movement of the jawsegments 150 from the first condition toward the second conditionpreferably causes substantially uniform movement of substantially theentire outer surface 135. As shown in FIGS. 2A and 2B, the jaw segments150 preferably are moved along substantially straight predeterminedpaths as the jaw segments 150 are moved from the first condition to thesecond condition, the predetermined paths being aligned with preselectedend points. In addition, as the jaw segments are moved from the secondcondition to the first condition, each jaw segment moves in the oppositedirection, along the same substantially straight path respectively.

For example, the design outer profile 138 for which the jaw segments 150shown in FIGS. 2A and 2B are designed is an oval. As can be seen in FIG.2A, the jaw segments 150 are formed to be arranged in four groups162A-162D of three jaw segments each. For convenience, the jaw segmentsare identified in FIG. 2A as jaw segments 150A-150L. As can be seen inFIG. 2A, in this example, jaw segments 150A-150C are included in a group(designated 162A) of three jaw segments which travel along substantiallystraight paths directed to a common focus (or common preselected endpoint) 164. Similarly, the jaw segments 150D-150F are in a group 162Bmoving along paths directed toward a common focus (preselected endpoint) 166. The jaw segments 150G-150I are in a group 162C and areadapted to move along paths toward a common focus (preselected endpoint) 168. The jaw segments 150J-150L are in a group 162D adapted tomove along paths towards a common focus (preselected end point) 170.

As shown in FIG. 2A, each jaw segment 150 moves along its respectivesubstantially straight path. For example, the jaw segment 150A movesalong the path 172A toward the preselected end point 164 (i.e., in thedirection indicated by arrow “B”) when the jaw segments are moving fromthe first condition to the second condition. It will be understood that,when the jaw segments are moving from the second condition to the firstcondition (e.g., after the housing 136 has been formed), the jaw segment150A moves along the path 172A in the opposite direction (i.e., in thedirection indicated by arrow “C”), away from the preselected end point164.

The other jaw segments 150B, 150C in group 162A move along differentpaths (identified as 172B and 172C respectively in FIG. 2A). However, asshown in FIG. 2A, all three jaw segments 150A-150C move toward the samepreselected end point 164 when the jaw segments are moving from thefirst condition to the second condition, and all three jaw segments150A-150C move away from the same preselected end point 164 when the jawsegments are moving from the second condition to the first condition. Itcan be seen from FIG. 2A that the jaw segments in the other groups162B-162D also move along respective paths which are to or from eachgroup's preselected end point respectively. In each case, thepredetermined paths for the jaw segments in a particular group convergeat the preselected end point. Preferably, the jaw segments in a groupare positioned adjacent to each other, as can be seen in FIG. 2A.

In FIG. 2A, the jaw segments are shown in the second condition. (It willbe understood that the gaps between the jaw segments as illustrated inFIG. 2A are exaggerated for clarity of illustration.) Accordingly, theinternal surfaces 156A-156L of the jaw segments in a group 162substantially define a portion of the design outer profile 138. Theportion is a part of an arc. Preferably, a radius “R” centered on thepreselected end point of a selected one of the groups is substantiallycoincident with a portion of the design outer profile that is defined bythe internal surfaces of the jaw segments in the selected one of thegroups, when the jaw segments are in the second condition.

For instance, the internal surfaces 156A-156C substantially define aportion of the design outer profile 138. The radius R, being the line172B between the preselected end point 164 and the internal surface 156B(as illustrated in FIG. 2A), is centered on the preselected end point164 and is coincident with the internal surfaces 156A-156C, being theinternal surfaces for the jaw segments 150A-150C in the group 162A,which is associated with the preselected end point 164. As can be seenin FIG. 2A, for the other groups 162B-162D, the radius centered on thepreselected end point for each group respectively is substantiallycoincident with the portion of the design outer profile 138 that issubstantially defined by the internal surfaces of the jaw segments ineach respective group.

The workpiece 132 is shown in dashed outline in FIG. 3, positioned tocorrespond to the housing 136 (with a brick 174 and a mat 176 therein)formed from the workpiece 132. The extent to which the outer profile 34is reduced to become the design outer profile 138 is identified in FIG.3 as “D”. In practice, the distance D may be between approximately 2millimeters and approximately 10 millimeters. As well, in the inventionherein, only one machine (i.e., the tool assembly 130 of the invention)is required to achieve the reduction.

As can be seen, for instance, in FIGS. 4 and 5, it is preferred thatsubstantially the entire outer surface 135 is engaged by the internalsurfaces of the jaw segments. It can also be seen in FIG. 3 that theinitial outer profile is offset outwardly from the design outer profileby a predetermined distance D. Because the jaw segments are moveduniformly inwardly as the jaw segments are moved from the firstcondition to the second condition, the movement of the outer surface 135from the initial position to the design position is substantiallyuniform. Accordingly, due to the engagement of substantially the entireouter surface 135 by the internal surfaces 156 of the jaw segments 150of the invention, the outer surface 135 is reduced from the initialposition to the design position without “ridges” developing on the outersurfaces between individual jaw segments. It has been found that suchreduction is made even where the reduction distance D is 2 millimetersor more.

As can be seen in FIGS. 4, 5, 6C, 6D, and 6E, in one embodiment, theinsert portion 146 and the ring portion 140 preferably are positioned ina frame 178 in which movement of the insert portion 146 relative to thering portion 140 is permitted. The manner in which the insert portion146 and the ring portion 140 are mounted in the frame 178 would be knownto those skilled in the art, and it is therefore unnecessary to describethe frame 178 in detail.

The engagement of the external surface 156 of a single jaw segment 150with the inner surface 144 as the jaw segment 150 is moved relative tothe ring portion 140 is shown in FIG. 9C. When the insert portion 146 ismoving from the first condition to the second condition, the jaw segment150 is moving in the direction indicated by arrow “J” in FIG. 9C. Due tothe taper of the external surface 156 and the shape of the inner surface144 of the ring portion 140, as the insert portion 146 is moved in thedirection of arrow “J”, the jaw segment 150 is also moved inwardly,i.e., in the direction indicated by arrow “K” in FIG. 9C, because thejaw segment 150 is urged inwardly as the inner surface 144 is engaged bythe external surface 158.

In one embodiment, the inner surface 144 substantially defines an offsetprofile which is offset outwardly from the design outer profile 138substantially by the thickness of each jaw segment 150. However, it willbe understood that many different arrangements are possible, and theinner surface 144 may have any suitable shape, depending in part on theform of the jaw segments.

It will be understood that the workpiece 132 and a number of elements inthe tool assembly 130 are omitted from FIG. 9C, to simplify the drawing.For instance, it will be understood that the back end 152 of the jawsegment 150 is engaged with the back plate 148 (not shown in FIG. 9C).

After the housing 136 has been formed, the insert portion 146 is movedfrom the second condition to the first condition, i.e., the insertportion 146 is moved in the direction indicated by arrow “L” in FIG. 9Crelative to the ring portion 140. Due to the tapered shape of the jawsegment 150, movement of the insert portion 146 to the first conditionalso causes movement of the jaw segment 150 outwardly, i.e., in thedirection indicated by arrow “M” in FIG. 9C.

It will be understood that, once the housing is formed (i.e., as shownin FIG. 5), the jaw segments are moved to the second (disengaged)condition, and the housing is then removed, usually with the brick andthe mat therein. Preferably, the jaw segments are moved from the secondcondition to the first condition due to the insert portion 146 movingfrom the closed condition to the open condition. After the housing 136is removed, the next workpiece 132 (usually, with the brick and the matpositioned therein) is then positioned in the jaw segments while the jawsegments are in the disengaged condition.

As shown in FIG. 6C, when it is intended to cause the jaw segments tomove from the first condition to the second condition, the insertportion 146 preferably is moved toward the ring portion 140, i.e., inthe direction indicated by arrow “E” in FIG. 6C. When the jaw segmentsare to be moved from the second condition to the first condition, theinsert portion 146 is moved away from the ring portion 140, i.e., in thedirection indicated by arrow “F” in FIG. 6C. (It will be understood thatthe frame 178 is not included in FIG. 6C for clarity of illustration.)

Although the insert portion 146 has been described as being movablerelative to the ring portion 140, it will be understood that otherarrangements are possible. For example, in an alternative arrangement,the ring portion 140 may be movable relative to the insert portion 146,i.e., with the insert portion 146 remaining stationary. Alternatively,both the insert portion 146 and the ring portion 140 may be movable,i.e., each may be movable relative to the other.

For clarity of illustration, only a completed housing 136 is shown inFIG. 4 as being engaged by the jaw segments 150, in the engagedcondition, i.e., the brick 174 and the mat 176 are not shown in FIG. 4for clarity. FIG. 5 shows the housing 136 as formed with the brick 174and the mat 176 therein, with the jaw segments 150 in the engagedcondition.

For exemplary purposes, the non-round design profile shown in thedrawings is an oval. However, it will be understood that the inventionmay be used to form a housing having any non-round shape, whetherregular or irregular. Depending on the size of the housing and the sizereduction required, the number of jaw segments may be greater or lessthan shown in the attached drawings. Also, the arrangement of the jawsegments into groups (each with a common focus) is dependent on, amongother things, the design outer profile and the extent of the sizereduction required.

INDUSTRIAL APPLICABILITY

In use, an embodiment of a method 453 of the invention includes thesteps of providing a ring portion (step 455, in FIG. 15A) and providingan insert portion (step 457). (It will be understood that the order inwhich steps 455 and 457 are performed may vary.) The jaw segments 150are at least partially positioned in the bore 142 of the ring portion140 (step 459). The jaw segments 150 preferably are moved to the firstcondition (step 461). The workpiece 132 is inserted in the opening 160(step 463). Preferably, the back plate 148 is then moved toward the ringportion 140, causing the jaw segments 150 to engage substantially all ofthe outer surface 135 of the workpiece 132 and reduce the outer surfacefrom the initial position thereof to the design position (step 465).

An alternative embodiment of the method of the invention 553 isschematically illustrated in FIG. 15B. The method 553 is the same as themethod 453, except that, instead of step 465, in the method 553, thering portion 140 is moved toward the back plate 148 (step 567, in FIG.15B). Another alternative embodiment of the method of the invention 653is disclosed in FIG. 15C. The only difference between the method 653 andthe other embodiments of the method 453, 553 is the final step. In themethod 653, the final step involves moving the back plate 148 and thering portion 140 toward each other (step 669, in FIG. 15C).

An additional embodiment of the invention is shown in FIGS. 6F, 6G, and10A-14. In FIGS. 6F, 6G, and 10A-14, elements are numbered so as tocorrespond to like elements shown in FIGS. 2A-6E and 7A-9C.

As illustrated in FIGS. 10A-12B, in an alternative embodiment of theinsert portion 246, the back plate 248 includes keyways 280. As can beseen, for example, in FIG. 12B, each jaw segment 250 preferably extendsbetween a front end 254 and a back end 252, and includes a key portion282 positioned at the back end 252. The key portion 282 is adapted to beslidably received in the keyway 280. The keyway 280 in the back plate248 is for guiding each jaw segment 250 along the predetermined paththerefor respectively. The keyway 280 for each respective jaw segment250 preferably is aligned with the appropriate respective path for thejaw segment 250, to keep the jaw segment 250 properly aligned (i.e.,moving along the predetermined path therefor) as the jaw segments aremoved between the first condition and the second condition.

As can be seen in FIG. 6G, the keyways 280 are positioned so as tocorrespond to the directions of movement of the jaw segmentsrespectively. In FIG. 6G, keyways 280A, 280B, and 280C are included in agroup 284A with a common focus (preselected end point) 286. Keyways280D, 280E, and 280F are included in a group 284B with a common focus(preselected end point) 288. Keyways 280G-280I are included in a group284C with a common focus 290. Keyways 280J-280L are included in a group284D with a common focus (preselected end point) 292.

It will be appreciated by those skilled in the art that various meansfor moving the jaw segments along predetermined paths (i.e., towardpreselected end points) so that the workpiece is substantiallysimultaneously engaged by the jaw segments may be suitable. Forinstance, another embodiment of the tool assembly 330 of the inventionis shown in FIGS. 13A, 13B and 14. The tool assembly 330 preferablyincludes a plurality of jaw segments 350 with respective internalsurfaces 356. As can be seen in FIGS. 13A, 13B, and 14, the jaw segments350 preferably are movable between a first condition (FIGS. 13A, 13B),in which an opening 360 is defined in which the workpiece 132 isreceivable, and an second condition (FIG. 14), in which the internalsurfaces 356 of the jaw segments 350 substantially define the designouter profile 138 of the housing 136. (For clarity of illustration, theworkpiece 132 and the housing 136 formed from the workpiece 132 are notshown in FIGS. 13A, 13B, and 14.)

As can be seen in FIGS. 13A, 13B, and 14, each jaw segment 350preferably is movable along a predetermined path toward a preselectedend point (i.e., a predetermined focus) therefor. The jaw segments 350preferably are also movable respectively along the predetermined paththerefor, away from the end point, or predetermined focus thereof.

In one embodiment, and as shown in FIGS. 13A, 13B, and 14, each jawsegment 350 preferably is at least partially movable along thepredetermined path therefor by one or more motive means 351. The motivemeans preferably is any suitable device. For instance, a hydrauliccylinder would be a suitable motive means. The hydraulic cylinderspreferably are controlled so that engagement of the jaw segments 350with the workpiece, to form the housing, is substantially simultaneous.Because of this, the workpiece 132 is formed into the housing 136 by thetool assembly 330, i.e., without seams or wrinkles.

For example, the design outer profile 138 for which the jaw segments 350shown in FIGS. 13A, 13B and 14 are designed is an oval. As can be seenin FIGS. 13A, 13B, and 14, the jaw segments 350 are formed to bearranged in four groups of three jaw segments each. For convenience, thejaw segments are identified in FIG. 13B as jaw segments 350A-350L. Ascan be seen in FIGS. 13A and 13B, in this example, jaw segments350A-350C are included in a group (designated 362A) of three jawsegments which travel along substantially straight paths directed to acommon focus (preselected end point) 364. Similarly, the jaw segments350D-350F are in a group 362B moving along paths directed toward acommon focus (preselected end point) 366. The jaw segments 350G-350I arein a group 362C and are adapted to move along paths toward a commonfocus (preselected end point) 368. The jaw segments 350J-350L are in agroup 362D adapted to move along paths towards a common focus 370.

As shown in FIGS. 13A, 13B, and 14, each jaw segment 350 moves along itsrespective substantially straight path, controlled by the motive means351 associated with each jaw segment 350 respectively. For example, thejaw segment 350A moves along the path 372A toward the point 364 (i.e.,in the direction indicated by arrow “G”) when the jaw segments aremoving from the first condition to the second condition. It will beunderstood that, when the jaw segments are moving from the secondcondition to the first condition, the jaw segment 350A moves along thepath 372A in the opposite direction (i.e., in the direction indicated byarrow “H”), away from the common focus 364 (preselected end point).

The other jaw segments 350B, 350C in group 362A move along differentpaths (identified as 372B and 372C respectively in FIG. 13B). However,as shown in FIG. 13B, all three jaw segments 350A-350C move toward thesame common focus (preselected end point) 364 when the jaw segments aremoving from the first condition to the second condition, and all threejaw segments 350A-350C move away from the same common focus 364 when thejaw segments are moving from the second condition to the firstcondition. It can be seen from FIGS. 13A, 13B, and 14 that the jawsegments in the other groups 362B-362D also move along respective pathswhich are to or from each group's common focus respectively. The motivemeans 351, each of which preferably controls movement of the one jawsegment 350, provides precise control of such movement.

As indicated above, where the design outer profile is a non-round shapewhich is not an oval, different arrangements of jaw segments would beused, and the balance of the insert portion and the ring portion wouldalso be modified as appropriate, depending on the design outer profile.In each case, selected jaw segments are moved to and from preselectedend points, and also the engagement of the jaw segments withsubstantially the entire outer surface of the workpiece is substantiallysimultaneous.

It will be appreciated by those skilled in the art that the inventioncan take many forms, and that such forms are within the scope of theinvention as claimed. For instance, other means for moving the jawsegments between the first and second conditions (e.g., ball screws, orvarious pneumatic or mechanical devices) may be used. The foregoingdescriptions are exemplary, and their scope should not be limited to thepreferred versions contained herein.

We claim:
 1. A tool assembly for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the tool assembly comprising: a ring portion comprising a bore therein at least partially defined by an inner surface; an insert portion comprising: a back plate; a plurality of elongate jaw segments, each said jaw segment extending between a back end thereof engaged with the back plate and a front end thereof distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two of said jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for sliding engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is receivable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned with a plurality of preselected end points, respectively, said preselected end points being respective points of convergence of said predetermined paths for the jaw segments in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; each said group of said jaw segments being associated with a selected one of said preselected end points, each said jaw segment in each said group being movable along the predetermined path therefor toward the selected one of the preselected end points for the group thereof as the jaw segments are moved from the first condition to the second condition; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated with each said preselected end point respectively, when the jaw segments are in the second condition; the jaw segments being at least partially receivable in the bore of the ring portion; the insert portion being movable relative to the ring portion between an open condition of the tool assembly, in which the back plate is positioned distal to the ring portion, and a closed condition of the tool assembly, in which the back plate is positioned proximal to the ring portion; and when the insert portion moves from the open condition to the closed condition, the inner surface of the ring portion urges the jaw segments inwardly from the first condition to the second condition, causing the jaw segments to engage substantially the entire outer surface of the workpiece and to move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 2. A tool assembly according to claim 1 in which movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of substantially the entire outer surface of the workpiece.
 3. A tool assembly according to claim 1 in which each said jaw segment comprises a key portion respectively, each said key portion being receivable in a keyway in the back plate for guiding each said jaw segment along the predetermined path therefor respectively.
 4. A tool assembly according to claim 1 in which each said jaw segment is movable along the predetermined path therefor by at least one motive means.
 5. A method for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the method comprising: (a) providing a ring portion comprising a bore therein defined by an inner surface; (b) providing an insert portion comprising: a back plate; a plurality of jaw segments, each said jaw segment extending between a back end thereof engageable with the back plate and a front end distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two of said jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is at least partially positionable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned respectively with a plurality of preselected end points therefor, said preselected end points being respective points of convergence of said predetermined paths for the jaw segments in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; each said group of said jaw segments being associated with a selected one of said preselected end points; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated therewith, when the jaw segments are in the second condition; the insert portion being movable relative to the ring portion between an open condition, in which the back plate is positioned distal to the ring portion, and a closed condition, in which the back plate is positioned proximal to the ring portion; (c) positioning at least parts of the jaw segments in the bore of the ring portion; (d) moving the jaw segments to the first condition; (e) inserting the workpiece in the opening; and (f) moving the back plate toward the ring portion to engage the inner surface of the ring portion with the external surfaces of the jaw segments, to urge the jaw segments inwardly along the respective predetermined paths to the second condition such that the internal surfaces of the jaw segments engage substantially the entire outer surface of the workpiece and move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 6. A method according to claim 5 in which, in step (f), the movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of the outer surface of the workpiece.
 7. A method according to claim 5 in which each said jaw segment is guided along the predetermined path therefor by a key portion thereof receivable in a keyway in the back plate.
 8. A method according to claim 5 in which each said jaw segment is moved along the predetermined path therefor by at least one motive means.
 9. A tool assembly for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the tool assembly comprising: a ring portion comprising a bore therein at least partially defined by an inner surface; an insert portion comprising: a back plate; a plurality of elongate jaw segments, each said jaw segment extending between a back end thereof engaged with the back plate and a front end thereof distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two of said jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for sliding engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is receivable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned with a plurality of preselected end points respectively, said preselected end points being respective points of convergence of said predetermined paths for the jaw segments in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; each said group of said jaw segments being associated with a selected one of said preselected end points, each said jaw segment in each said group being movable along the predetermined path therefor toward the selected one of the preselected end points for the group thereof as the jaw segments are movable from the first condition to the second condition; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated with each preselected end point respectively, when the jaw segments are in the second condition; the jaw segments being at least partially receivable in the bore of the ring portion; the ring portion being movable relative to the insert portion between an open condition of the tool assembly, in which the ring portion is positioned distal to the back plate, and a closed condition of the tool assembly, in which the ring portion is positioned proximal to the back plate; and when the ring portion moves from the open condition to the closed condition, the inner surface of the ring portion urges the jaw segments inwardly from the first condition to the second condition, causing the jaw segments to engage substantially the entire outer surface and to move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 10. A tool assembly according to claim 9 in which movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of substantially the entire outer surface of the workpiece.
 11. A tool assembly according to claim 9 in which each said jaw segment comprises a key portion respectively, each said key portion being receivable in a keyway in the back plate for guiding each said jaw segment along the predetermined path therefor respectively.
 12. A tool assembly according to claim 9 in which each said jaw segment is movable along the predetermined path therefor by at least one motive means.
 13. A method for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the method comprising: (a) providing a ring portion comprising a bore therein defined by an inner surface; (b) providing an insert portion comprising: a back plate; a plurality of jaw segments, each said jaw segment extending between a back end thereof engageable with the back plate and a front end distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two of said jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is at least partially positionable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned respectively with a plurality of preselected end points therefor, said preselected end points being respective points of convergence of said predetermined paths in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated therewith, when the jaw segments are in the second condition; the ring portion being movable relative to the insert portion between an open condition, in which the ring portion is positioned distal to the back plate, and a closed condition, in which the ring portion is positioned proximal to the back plate; (c) positioning at least parts of the jaw segments in the bore of the ring portion; (d) moving the jaw segments to the first condition; (e) inserting the workpiece in the opening; and (f) moving the ring portion toward the back plate to engage the inner surface of the ring portion with the external surfaces of the jaw segments, to urge the jaw segments inwardly along the respective predetermined paths to the second condition such that the internal surfaces of the jaw segments engage substantially the entire outer surface of the workpiece and move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 14. A method according to claim 13 in which, in step (f), the movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of the outer surface of the workpiece.
 15. A method according to claim 13 in which each said jaw segment is guided along the predetermined path therefor by a key portion thereof receivable in a keyway in the back plate.
 16. A method according to claim 13 in which each said jaw segment is moved along the predetermined path therefor by at least one motive means.
 17. A tool assembly for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the tool assembly comprising: a ring portion comprising a bore therein at least partially defined by an inner surface; an insert portion comprising: a back plate; a plurality of elongate jaw segments, each said jaw segment extending between a back end thereof engaged with the back plate and a front end thereof distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two of said jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for sliding engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is receivable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned with a plurality of preselected end points, respectively, said preselected end points being respective points of convergence of said predetermined paths for the jaw segments in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; each said group being associated with a selected one of said preselected end points, each said jaw segment in each said group being movable along the predetermined path therefor toward the selected one of the preselected end points for the group thereof as the jaw segments are moved from the first condition to the second condition; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated with each said preselected end point respectively, when the jaw segment are in the second condition; the jaw segments being at least partially receivable in the bore of the ring portion; the insert portion and the ring portion being movable relative to each other between an open condition of the tool assembly, in which the back plate is positioned distal to the ring portion, and a closed condition of the tool assembly, in which the back plate is positioned proximal to the ring portion; and when the ring portion and the insert portion move from the open condition to the closed condition, the inner surface of the ring portion urges the jaw segments inwardly from the first condition to the second condition, causing the jaw segments to engage substantially the entire outer surface and to move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 18. A tool assembly according to claim 17 in which movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of substantially the entire outer surface of the workpiece.
 19. A tool assembly according to claim 17 in which each said jaw segment comprises a key portion respectively, each said key portion being receivable in a keyway in the back plate for guiding each said jaw segment along the predetermined path therefor respectively.
 20. A tool assembly according to claim 17 in which each said jaw segment is movable along the predetermined path therefor by at least one motive means.
 21. A method for forming a workpiece with an initial outer profile at least partially defined by an outer surface thereof at an initial position into a housing with a non-round design outer profile at least partially defined by the outer surface at a design position reduced from the initial position thereof, the method comprising: (a) providing a ring portion comprising a bore therein defined by an inner surface; (b) providing an insert portion comprising: a back plate; a plurality of jaw segments, each said jaw segment extending between a back end thereof engageable with the back plate and a front end distal to the back plate; said jaw segments being divided into a plurality of groups, each said group comprising at least two jaw segments; each said jaw segment comprising an internal surface for engaging the outer surface and an at least partially tapered external surface for engagement with the inner surface of the ring portion; the jaw segments being movable along respective substantially straight predetermined paths between a first condition, in which the internal surfaces of the jaw segments at least partially define an opening in which the workpiece is at least partially positionable, and a second condition, in which the internal surfaces of the jaw segments substantially define the design position of the outer surface; each said predetermined path extending at an angle normal to said internal surface of the respective jaw segment therefor; the predetermined paths being aligned respectively with a plurality of preselected end points therefor, said preselected end points being respective points of convergence of said predetermined paths for the jaw segments in the respective groups of jaw segments, and each of the preselected end points being located physically and spatially separate from each other; each said group being associated with a selected one of said preselected end points; for each of the preselected end points, a radius centered thereon being substantially coincident with a portion of the design outer profile that is substantially defined by the internal surfaces of the jaw segments in the group associated therewith, when the jaw segments are in the second condition; the insert portion and the ring portion being movable relative to each other between an open condition, in which the back plate is positioned distal to the ring portion, and a closed condition, in which the back plate is positioned proximal to the ring portion; (c) positioning at least parts of the jaw segments in the bore of the ring portion; (d) moving the jaw segments to the first condition; (e) inserting the workpiece in the opening; and (f) moving the back plate and ring portion toward each other to engage the inner surface of the ring portion with the external surfaces of the jaw segments, to urge the jaw segments inwardly along the respective predetermined paths to the second condition such that the internal surfaces of the jaw segments engage substantially the entire outer surface of the workpiece and move the outer surface from the initial position to the design position, reducing the initial outer profile to the design outer profile and forming the workpiece into the housing.
 22. A method according to claim 21 in which, in step (f), the movement of the jaw segments from the first condition toward the second condition causes substantially uniform movement of the outer surface of the workpiece.
 23. A method according to claim 21 in which each said jaw segment is guided along the predetermined path therefor by a key portion thereof receivable in a keyway in the back plate.
 24. A method according to claim 21 in which each said jaw segment is moved along the predetermined path therefor by at least one motive means. 